Demonstrators hold a vigil on July 31, 2013, for family members who were being held in a detention facility in Eloy. / Nick Oza, The Arizona Republic

by Daniel González, The Arizona Republic

by Daniel González, The Arizona Republic

PHOENIX -- Immigration and Customs Enforcement officials are still refusing to disclose the names, criminal histories and whereabouts of more than 2,200 detainees the agency suddenly released a year ago.

Citing public-safety concerns, an array of public officials have demanded that ICE turn over details about the detainees, more than 300 of whom were set free in Arizona.

The officials include Gov. Jan Brewer; Pinal County Sheriff Paul Babeu; Arizona's U.S. senators, John McCain and Jeff Flake; and several other members of Congress.

But ICE officials have trickled out only limited information, including some documents obtained by The Arizona Republic that show that several detainees who were released had more serious criminal histories than ICE officials originally disclosed.

Other documents obtained by The Republic show that dozens of the detainees were later taken back into custody, including four of 10 detainees deemed Level 1, the highest risk.

Still, ICE has refused to turn over details about the vast majority of the more than 2,200 detainees released at the end of last February, including the total taken back into custody, how many remain free and whether any committed crimes after they were released.

At the time of their release, all were facing deportation.

ICE's refusal to fully disclose information about the released detainees and what happened to them has frustrated critics concerned that they put the safety of Americans at risk.

The lack of information also has complicated the ongoing debate in Washington over immigration reform by providing ammunition to Republican lawmakers who say they don't trust President Barack Obama's administration to enforce immigration laws.

At the same time, advocates on the other side of the immigration debate are also frustrated. They believe the mass release exposed how the government is detaining immigrants who shouldn't be held in the first place.

"What it did for us is show that detention is pretty arbitrary," said Silky Shah, interim executive director of Detention Watch Network, which advocates for reforms of the U.S. immigration detention system. "It points to the fact that we have right now a system that is required to funnel a certain number of people into detention."

By withholding information about the detainees, ICE is missing out on a chance to dispel some of the fears raised by critics, she said.

"I think it's a missed opportunity, absolutely, just to say that nothing bad happened after these releases," Shah said.

During the last week of February 2013, ICE officials said they released 2,228 immigration detainees from facilities across the country.

At the time, ICE said the number of immigrants being held in detention had exceeded the 34,000 quota mandated by Congress.

ICE officials said the agency needed to reduce the overall number of immigrants being held in order to avoid a cost overrun because funding for the year was about to end and automatic budget cuts known as the sequester were about to begin.

The officials said they reviewed the backgrounds and criminal histories of all the detainees who were released beforehand to ensure they did not pose a significant threat to public safety.

The mass release, however, prompted outrage from Arizona politicians as well as many Republicans in Congress who demanded that ICE turn over more details about the released detainees.

During House hearings, Republicans also blasted ICE officials for releasing detainees who included immigrants with criminal backgrounds that could endanger the public.

Meanwhile, some Democrats raised concerns that ICE was spending money on detaining immigrants who posed little risk to the public and were unlikely to flee.

In early February of this year, The Republic wrote to ICE asking the agency to release information about the detainees who had been set free a year ago, including how many had been taken back into custody and whether any had committed any crimes after their release. The Republic also filed a Freedom of Information Act request seeking the same information.

In response, ICE officials would say only that individual detainees who remain free continue to be monitored by ICE field offices around the country to make sure they remain in compliance with the conditions of their release.

The FOIA request is still pending.

The Republic did obtain some documents ICE had previously released to lawmakers last year, including copies of letters ICE officials wrote in response to requests for information about the released detainees.

Those documents show that in Arizona, ICE officials released a detainee whose criminal convictions included felony second-degree robbery, prostitution and solicitation for lewd conduct, the documents show.

Another detainee released in Arizona had been convicted of DUI and harassment after having caused criminal damaged to property, the documents show.

Both detainees were taken back into custody by ICE in March 2013 and then released again after an immigration judge granted them bond, according to ICE officials. They continue to be monitored by ICE while their cases are pending.

A third had prior convictions for carrying a loaded firearm, DUI with controlled substance, felony possession of drugs, second-degree burglary, vandalism and trespassing, the documents show.

That detainee was deported to Mexico in May, ICE officials say.

In San Francisco, ICE officials released a detainee with a prior felony conviction for manufacturing fake IDs and a detainee with two DUI convictions and two stalking convictions.

In Houston, ICE released a detainee who had a prior conviction for felony possession of marijuana.

The Republic also obtained documents detailing the criminal backgrounds of the 10 released detainees deemed Level 1, the highest-risk detainees, and updates about their cases.

Those documents show that four of the 10 Level 1 offenders were taken back into custody, then freed again after they posted bond or their cases were terminated. Two of the 10 were deported. Four remain free under ICE supervision, including Victor Mendoza Medina, whom The Republic profiled in April after tracking him down in New York City following his release from a detention center in Eloy.

Medina, a 69-year-old Bolivian immigrant, was classified as Level 1 because he had multiple criminal convictions for drug possession, theft and possession of stolen property, but he had no convictions for violent crimes and had lived in the U.S. legally for more than 45 years.

McCain attempted to find out more about the criminal backgrounds of the detainees who were released as part of his role as ranking Republican member of the U.S. Senate Permanent Subcommittee on Investigations.

He and Sen. Carl Levin, D-Mich., the panel's chairman, did get some response, but it wasn't "as complete as we wanted," McCain said.

"We never really got very satisfactory answers on that," McCain told The Republic.

"They blamed it on the local ICE people, that they had acted without authorization. They blamed it on lower-level individuals."